Pixel circuit selecting to output time difference data or image data

Abstract

There is provided a pixel circuit capable of outputting time difference data or image data, and including a first temporal circuit and a second temporal circuit. The first temporal circuit is used to store detected light energy of a first interval and a second interval as the time difference data. The second temporal circuit is used to store detected light energy of the second interval as the image data. The pixel circuit is used to output a pulse width signal corresponding to the time difference data or the image data in different operating modes.

What is claimed is: 
     
       1. A pixel circuit, comprising:
 a photodiode, configured to generate light energy; 
 a first temporal circuit, comprising:
 a first capacitor having a first end coupled to the photodiode; 
 
 a second temporal circuit, comprising:
 a second capacitor having a first end coupled to the photodiode; 
 
 a first comparator, comprising:
 a first input transistor, arranged inside the first temporal circuit and connected to a second end of the first capacitor; and 
 a second input transistor, arranged outside the first temporal circuit and shared with other pixel circuits; 
 
 a second comparator, comprising:
 a third input transistor, arranged inside the second temporal circuit and connected to a second end of the second capacitor; and 
 a fourth input transistor, arranged outside the second temporal circuit and shared with the other pixel circuits; 
 
 a transfer transistor, connected between the photodiode and the first end of the first capacitor as well as the first end of the second capacitor, and configured to transfer the light energy to the first temporal circuit in a first interval and a second interval, and transfer the light energy to the second temporal circuit in the second interval; and 
 a reset transistor, connected between the transfer transistor and the first end of the first capacitor as well as the first end of the second capacitor, wherein 
 the first temporal circuit further comprises a second transistor connected between the first capacitor and the first input transistor, 
 the second temporal circuit further comprises a second transistor connected between the second capacitor and the third input transistor, and 
 the second transistor of the first temporal circuit is not conducted in the second interval, and the second transistor of the second temporal circuit is not conducted in the first interval. 
 
     
     
       2. A pixel circuit, comprising:
 a photodiode, configured to generate light energy; 
 a first temporal circuit, comprising:
 a first capacitor having a first end coupled to the photodiode; 
 
 a second temporal circuit, comprising:
 a second capacitor having a first end coupled to the photodiode; 
 
 a first comparator, comprising:
 a first input transistor, arranged inside the first temporal circuit and connected to a second end of the first capacitor; and 
 a second input transistor, arranged outside the first temporal circuit and shared with other pixel circuits; 
 
 a second comparator, comprising:
 a third input transistor, arranged inside the second temporal circuit and connected to a second end of the second capacitor; and 
 a fourth input transistor, arranged outside the second temporal circuit and shared with the other pixel circuits; 
 
 a transfer transistor, connected between the photodiode and the first end of the first capacitor as well as the first end of the second capacitor, and configured to transfer the light energy to the first temporal circuit in a first interval and a second interval, and transfer the light energy to the second temporal circuit in the second interval; and 
 a reset transistor, connected between the transfer transistor and the first end of the first capacitor as well as the first end of the second capacitor, wherein 
 the first temporal circuit is configured to record a light energy variation from the photodiode between the first interval and the second interval, and
 the second temporal circuit is configured to record detected light energy from the photodiode in the second interval. 
 
 
     
     
       3. The pixel circuit as claimed in  claim 2 , wherein the second input transistor is configured to
 receive a ramp signal to cause the first temporal circuit to output a pulse width signal corresponding to the light energy variation, or 
 sequentially receive an upper threshold voltage and a lower threshold voltage to confirm whether the light energy variation exceeds the upper threshold voltage or the lower threshold voltage. 
 
     
     
       4. The pixel circuit as claimed in  claim 2 , wherein the fourth input transistor is configured to
 receive a ramp signal to cause the second temporal circuit to output a pulse width signal corresponding to the detected light energy. 
 
     
     
       5. A pixel circuit, comprising:
 a photodiode, configured to generate light energy; 
 a first temporal circuit, comprising:
 a first capacitor having a first end coupled to the photodiode; 
 
 a second temporal circuit, comprising:
 a second capacitor having a first end coupled to the photodiode; 
 
 a first comparator, comprising:
 a first input transistor, arranged inside the first temporal circuit and connected to a second end of the first capacitor; and 
 a second input transistor, arranged outside the first temporal circuit and shared with other pixel circuits; 
 
 a second comparator, comprising:
 a third input transistor, arranged inside the second temporal circuit and connected to a second end of the second capacitor; and 
 a fourth input transistor, arranged outside the second temporal circuit and shared with the other pixel circuits; and 
 
 multiple row selection transistors connected between the first temporal circuit and the first comparator and between the second temporal circuit and the second comparator.